A heat exchanger in a heat-pump type air conditioner of a vehicle equipped with an engine is disclosed in Patent Literature 1. In this heat exchanger (functioning as a condenser or an evaporator), a pair of headers are connected together to communicate with the same end side of the upstream and downstream tube groups each having a plurality of stacked refrigerant circulation tubes. Portions of internal spaces of the pair of headers are connected together in communication with each other via a connecting member.
Hence, a counter-flow structure, in which a refrigerant flown in from the upstream tube group is caused to flow out to the downstream tube group, is formed to enable the heat exchange efficiency with the blown air to be improved. Further, when it is used as a vehicle interior heat exchanger, the temperature of the air (heating air or cooling air) blown to the vehicle interior can be homogenized.